intro
Purpose:
- Validate runwise ub55 GLMs in terms of marginal HRFs (averaged across conditions) and high-vs-low contrast.
- Define target TRs for each task.
- Calculate HiLo conjunction effect, and create list of conjunction parcels.
Notes on analyses:
GLMs:
- DMCC55B
- run-wise, 1trpk, shifted TENTs
- Cuedts: terms for \(\text{trial-type (congr, incon)}\times\text{sequence (switch, repeat)}\) instead of \(\text{incentive}\)
Target TRs:
- Axcpt: 7, 8, 9
- Cuedts: 9, 10
- Stern: 11, 12
- Stroop: 2, 3, 4
- Axcpt, Cuedts, and Stern begins at roughly ~4 TRs post-cue onset, and ending at ~8 TRs post-cue onset
- Stroop begins at 2 TRs post-target onset, ends at 6 TRs post-target onset
Contrasts (on regional means):
- Axcpt: \(\text{BY} - \text{BX}\)
- Cuedts: \((\text{InConSwitch} + \text{InConRepeat} - \text{ConSwitch} - \text{ConRepeat})/2\)
- Stern: \(\text{LL5RN} - \text{LL5NN}\)
- Stroop: \((\text{PC50InCon} + \text{biasInCon} - \text{PC50Con} - \text{biasCon})/2\)
Plotting and statistical details:
- within ‘curves’ sections, ribbons indicate 95% CI of bootstrapped mean beta across subjects (one ribbon per run).
- all p-value corrections were performed whole-cortex, with FDR.
- for “stats and maps” sections, HLM was used to estimate t-statistics on the hi-lo contrast per ROI:
- random-intercept models
- level-I: (TR within target window)*(run)
- level-2: subject
- \(\beta_{trs} = b_0 + d_s + \epsilon_{trs}\)
- \(\beta_{trs}\) is high-low contrast beta estimate
- \(t, r, s\) are indices for TR, run, and subject
- \(d\) is is subject-specific intercept
- \(\epsilon\) is error
Network-level
Estimates are first averaged across parcels within network per subject. Group-level stats and plots are then displayed at the network-level.
Parcel-level
counts of significant effects per TR
Using t-test of subject parcel means, averaged across run. Negative counts show deactivations.

contrasts
Cross-task conjunction (“DMCC55B parcels”)
Here conjunction analysis is performed by feeding TR-level contrast estimates to an HLM (see description at beginning of doc).
Number of parcels identified, and parcel names:
| Axcpt |
123 |
| Cuedts |
108 |
| Stern |
34 |
| Stroop |
176 |
Brains (contrasts)
NB: colors are reversed (black = high, yellow = low) so large positive effects can be seen on white underlay.